The original idea, to replace the wall-mounted thermostat system, was born in a recent Electric Imp Hackathon. Later on this concept would develop into the shelºF three part solution consisting of an actuator, sensor and controller. But the design of the project was decided very early on, especially regarding the sensor and the controller.
The sensor had to blend into the home, the issue with the wall-mounted unit is that no matter how pretty you make it, like Nest's product, it still can clash with the overall design of your home. The first solution, which eventually led to the TempBook board, was to put the sensor in a hollowed-out book. This is an item that is abundant in most homes and therefore goes by unnoticed, and it can be built very easily (tutorial I used). Future solutions would involve other hidden, easy to set up objects, such as a plant pot or a picture frame.
The controller had to be very simple and intuitive, while breaking with the original thermostat controls. The resulting design was a comfort-based system, where the user choses if they feel cold, cool, ok, warm or hot. While this is not the conventional system it gets rid of the confusing numbers that no one needs to know, since all that matters is how you feel.